The PH28 is a pulse width modulated ac to dc power converter that provides regulated 4-28 Vdc output with up to 10 amperes continuous output current. This converter is primarily designed for 115V/400 Hz aircraft systems to deliver variable 4 to 28 Vdc power to incandescent lamps or LED loads for airborne/ground instruments, navigation and electronic systems. The unit can also be used as a fixed output voltage source between 14 Vdc and 28 Vdc.

The DC output is factory calibrated to 28 Vdc at the receptacle for a 10 amp load. The output voltage level is controlled manually by the duration of grounding the Dim or Bright control pin through an external momentary On-Off toggle switch.

Withstands without damage or degradation load exceeding 110% to an output short circuit. Unit delivers rated output power upon removal of the overload condition

Protection(SC):

Under a output short circuit condition, the input and output currents pump and the currents are limited to safe values.

Control:

The output voltage is increased by grounding pin G and decreased by grounding pin A. When the ground is removed (OFF) the output voltage stops changing. The total time it takes from BRT to DIM (or DIM to BRT) using a continuous grounding is about 7 seconds. For faster and smoother control, apply grounding On and Off at appropriate rate by hand until a desired brightness or dimming is obtained. A minimum duration of one millisecond grounding is required to advance the output voltage one increment. There are total of 64 increments from full bright to dim or dim to full bright. (See Output Voltage Control Graph)